Shell making



Sept. 7, 1965 E. J. JusTUs ETAL 3,205,128

SHELL MAKING Filed Jan. 22, 1962 17 Sheets-Sheet l 557.1 A ZZ 37 warf 'l a (007km l INVENTORJ dy a7' J Jusfus BY Danad f ra/fard Sept 7, 1965 E. J. JUsTus ETAL 3,205,128

SHELL MAKING 17 Sheets-Shee'cl 2 Filed Jan. 22, 1962 TIMER SEQUENCE Sept. 7, 1965 E. J. Jus-rus ETAL 3,205,128

SHELL MAKING Filed Jan. 22, 1962 17 Sheets-Sheet 3 (ONROL Sept 7, 1965 E. J. .JusTus ETAL. 3,205,128

SHELL MAKING a waasef 77: w 44, y ATTORNEYS SePt- 7, 1965' E. J. JusTus ETAL 3,205,128

SHELL MAKING Filed Jan. 22, 1962 17 Sheets-Sheet 6 ATTORNEYS Sept 7, 1965 E. J. JusTus ETAL 3,205,128

SHELL MAKING 17 sheets-sheet 7 Filed Jan. 22, 1962 sept. 7, 1965 Filed Jan. 22, 1962 fafa,

E. J. JUSTUS ETAL SHELL MAKING 17 Sheets-Sheet 8 fdl la j INVENTORJ ioyd l/ornzas te( ATTORNEYS SHELL MAKING Filed Jan. 22, 1962 17 Sheets-Sheet 9 FRM CL50/V PRESI Sept. 7, 1965 E.J.Jus1us ETAL 3,205,123

SHELL MAKING I Filed Jan. 22, 1962 17 Sheets-Sheet 10 "Ulm,

INVENTOR` dgar J. Jus-us Dana (d 2%. Erafard INVENTOR` Sept. 7, 1965 E. J. Jus-rus ETAL SHELL MAKING Filed Jan. 22. 1962 17 Sheets-Sheet 1l @QN QN NQN @N 2N a Q m NNN o o uwi o o QQN Il lllll- U m m1 NN WH Sept- 7, 1965 E. J. JUsTUs ETAL 3,205,128

SHELL MAKING Filed Jan. 22, 1962 17 Sheets-Sheet 12 j? fz UNL 0170 I NVE'N TOR Edyar J Jus fus Y Pana. fabi raford .297920 fd J R067@ /o d fla/'2250.5 efJr' ATTORNEYS E. J. JUsTUs ETAL 3,205,128

SHELL MAKING I 17 Sheets-Sheet 13 sept. 7, 1965 Filed Jan. 22, 1962 Sept- 7, 1965 E. x. JUsTus ETAL 3,205,128

SHELL MAKING Filed Jan. 22. 1962 17 Sheets-Sheet 14 t@ y lo a arndsze J7.'

f M Y TTORNEYS Sept- 7, 1965 E. J. JUsTUs ETAL 3,205,128

SHELL MAKING Filed Jan. 22, 1962 17 Sheets-Sheet 15 Sept- 7, 1965 E. J. JUsTus ETAL I 3,205,128

SHELL MAKING 17 Sheets-Sheet 16 Filed Jan. 22, 1962 Sept. 7, 1965 E. J. JUsTUs ETAL 3,205,128

SHELL MAKING Filed Jan. 22, 1962 17 Sheets-Sheet 17 I *ff/f6 j] g )Il -J IV V7- 7.22 i ,f i s 111 f d f3.1 In

United States Patent O 3,205,128 SHELL MAKING Edgar J. Justus, Donald A. Bralford, Arnold I. R oerig,

and 'Lloyd Hornbostel, Jr., all of Beloit, Wis., asslgnors to Beloit Iron Works, Beloit, Wis., a corporation of Wisconsin Filed Jan. 22, 1962, Ser. No. 168,588 12 Claims. (Cl. 162-401) The present invention relates to an improved apparatus and method for forming shells or hollow forms from a liquid suspension of fibers.

More particularly, the invention pertains to forcing a fluid stock having a suspension of particles or fibers through the porous wall of a mold to deposit the fibers on a forming surface to directly form an article or shell of a desired shape. The apparatus and method are particularly well adapted to the formation of hollow tubular shaped thin walled shells which are uniform in thickness and have an accurate outer dimension and are strong. The manufacture of these shells in accordance with the principles of the invention involves forming by depositing fibers from the stock on the wall of the form, impregnating the shell with an impregnant binder, sizing the shell to an accurate shape and size, subjecting the shell to controlled drying and curing operations and trimming the edges of the shell. As will be understood from the description and claims, certain steps of the operation may be varied or performed in different sequences and portions of the operations may be used in various environments taking advantage of the features of the invention which lie in the combinations and subcombinations herein disclosed.

The mechanism and apparatus of the invention overcome certain difficulties inherent in the formation of a thin walled shell which in previous arrangements made it dicult to control accurate sizing and uniform formation of `the shell. Difficulties were also encountered in the handling and transfer of the shell particularly where manufacture on the basis of a substantial production was contemplated. The present arrangement is particularly well suited to rapid production operation for the mass production of shells. As will be understood the shells have various useful purposes such as foi-'containers wherein a strong, light weight shell or casing is required having an outer surface free of imperfections, and wherein a tubular shell must be provided of a predetermined linear outer profile with an accurate circular cross section and having an accurate outer diameter.

An object of the present invention is to provide an improved method and mechanism for making hollow shells wherein the shells are accurately formed and sized on the inner surface of a hollow mold.

A further object of the invention is to provide an improved method and mechanism for the improved depositing of fibers on the surface of a perforate mold for the formation of a shell of uniform diameter, accurately controlling the supply of stock to the mold and the ow of fluid through the mold wall for improved depositing of fibers.

A further object of the invention is to provide an improved mechanism and method for handling and transferring a hollow shell formed of deposited fibers for impregnating the fibers with a binder and for drying and sizing the shell.

A further object of the invention is to provide an improved arrangement for controllably drying an exposed surface of the formed shell and separating the uneXposed surface from the mold while it is moist.

A still further object of the invention is to provide anl improved machine which will rapidly produce hollow shells transporting them through a sequence of manuice a minimum cost and with a minimum of manufacturing delay.

Another object of the invention is to provide a mechanism employing improved basic operational steps which can be interchanged for the selection of different manu# facturing processes.

Other objects, advantages and features will become more apparent with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiments thereof, in the specilication, claims and drawings, in which:

FIGURE l is a side elevational View shown in somewhat schematic form, with parts broken away, of mechanism at a station in the machine for forming a hollow shell;

FIGURE 2 is a side elevational view similar to FIG- URE l showing a modified arrangement for forming the shell;

FIGURE 3 .is a sectional view taken through .the .machine showing a station for pressing the shell;

FIGURE 4 is a vertical sectional view taken through the Vmachine showinga station for impregnating the shell with a binder;

FIGURE 5 is a vertical sectional view taken through the machine showing a station for drying the shell;

FIGURE 6 is a vertical sectional view taken through the machine showing a station for removing the shell from the mold;

FIGURE 7 is a diagrammatic showing separate processes for forming shells utilizing the mechanism of the stations of FIGURES 1 through 6;

FIGURE 8 is an end elevational view of a form of mechanism forthe mold;

FIGURE 9 is a front elevational view of a portion of the machine of FIGURE 8, showing the first four stations of the machine;

FIGURE 10 is a front elevational view of the machine of FIGURES 8 and 9' showing the last four stations of the machine, and is to be viewed in conjunction with FIGURE 9;

FIGURE ll is a top plan view of the mechanism of FIGURE 9;

FIGURE 12 is a top plan view, with parts broken away, showing a drying mechanism for the machine;

FIGURE 13 is a side elevational View, with parts broken away showing the drying mechanism of FIG- URE l2;

FIGURE 14 is a top plan View showing a modified form of mechanism for performing some of the steps in the manufacture of the shells;

FIGURE 15 is a vertical sectional view taken substantially along Iline XV-XV of FIGURE 14;

FIGURE 16 is a vertical sectional view taken substantially along line XV I-XV I of FIGURE 14; and

FIGURE 17 is a vertical sectional view taken substantially along line XVIIXVII of FIGURE 14.

As `shown on the drawings:

As shown in FIGURE l, the mechanism is arranged to provide a stock S in a controlled quantity and at a controlled rate of liiow'to a mold `10 .which is illustrated as being tubular in :shape and circular in cross section, and has a predetermined linear configuration tapering slightly inwardly at the upper end. The mold lis supported within la housing r11 provi-ding a chamber 12 surrounding lthe mold for the application of vacuum or pres` sure to the mold in yorder to `create a pressure differential across the mold wall.y

The mold is porous .and Yis 'formed of the material such as individual glass beads coated with an .epoxy resin to bind the rbeads together in the mold shape. A 'further description of la pre'ferred `,form of mold material and the method of rmaking the material is provided in the copending patent application of Charles W. Modersohn and Lloyd Hornbostel, Jr., ent-itled Mo1d, U.S. Serial No. 89,451, tiled February 15, 1961, now abandoned.

The yfluid stock which is supplied to the interior of the mol'cl may be of the general nature ofsto'ck used in the formation of pa er. More particularly, the stock is preferably water with particles or bers in'suspension at a consistency of 0.01% to 2.0% and a preferred consistency of 0.05% `is employed. Particles or fibers suitable for the ,formation o'f the desired shell are in suspension in the water, and a preferred arrangement employs a Kraft pulp comprising 40% Kraft fibers and 60% cotton linter-s. This obtains a strong shell wall and provides features well suited for the mechanism and process to be described. The stock also may contain additional material such as a compatible resinous impregnant and/or binder, e.g., urea-formaldehyde or melamine-formaldehyde resins, cellulose esters and ethers, polyvinyl alcohols, etc.

Forming station For depositing the stock ina uniform layer on the inner surface o'f the mold, the stock is flowed through the center of the mold at a low velocity to avoid washing the deposited layer. A velocity of 2 to 3 feet per second or less should be used.

The mold housing t11 has a vacuum connect-ion 13, a stock inlet 14 and a stock outlet 15.

The housing with the mold supported therein moves through a series of stations for different operations in the formation of the shell, which are arranged along the path. The path extends along a top surface 16 of a machine table 17. The mold housing is suitably supported and moved `through the different stations of the path 'by a conveying mechanism which will be described.

For supplying stock to the interior of the mold 10, a mold supply conduit 1S is in alignment with the opening 14 at the bottom of the mold housing and a return conduit 19 is in alignment with the top opening 15 of the mold housing. The pressure in the vacuum chamber 12 is controlled by -a pressure line 21 which connects to the housing connection 13 through a suitable means such as a sliding coupling 20, and the vacuum and air pressure line 21 may -be moved along with the housing, or there may be a separate line provided at each station to be connected to the housing when it stops at the various stations. A 'control valve 22 is provided in the line 21 and the valve connects to a vacuum supply through line 23 and to a pressure supply through line 24, and these may be provided by suitable vacuum pumps and pressure pumps which are of conventional structure and need not be shown.

Stock dispersing means are provided within the mold 10 for an improved dispersion of 'the fibers within the liquid to aid distribution of the `fibers as they collect on an inner smooth forming surface 25 of the mold. For this purpose a shaped tubular screen 26 is removably positioned within the mold 10 and the perforations in the screen cause a dispersion of the fibers just before they reach the forming surface 25. Also located centrally within the mold is ia rotating agitator 27 driven by a motor 28.

Continued dispersion of the fibers to improve their deposition on the mold, and to avoid floccul-ation is also obtained by constant circulation tof the stock. The stock returns through a down line 29 which passes through the floor F, and is continually circulated by a circulating pump 30.

In 'the arrangement of FIGURE l -a predetermined quantity of stock is supplie-d to form a shell of a predetermined thickness. Stock S is supplied from a stock supply tank 31 having a power driven rotating agitator 32 therein. The level of the stock is controlled by a level control 33 which may be operated in coordination with a flow control 35 in a line 31a leading from the tank 31, to dispense a predetermined quantity Iof stock to the line 29. Stock is supplied by stock pump 34, and a shutoff valve 36 is positioned in the line 31a.

`Before a shell is formed, a predetermined quantity of stock is `fed into the line 29 and into the loop including conduits 18, `19 and 29. lf the loop is not full the loop is then filled by water from a line 37u -having a control valve 37 therein. While the loop is 'being filled, the housing chamber 12 is pressurized to avoid the lformation of any layer of stock on the forming surface 25. When the loop has been filled with the mixture of stock and water, the valve 22 is operated to create a vacuum in the chamber 12 and the pressure differential across the mold 10 will force stock through the porous mold and deposit fibers to form a shell on the forming surface 25. The pressure differential is 'maintained for a period of time with the loop being kept Ifull with a supply of water through the operations of the llow control valve 37. The measured amount of Astock will cause a lshell of a predetermined thickness to form. At the end of the shell forming time, .the line 37a lis connected to a dump conduit, and valve 37 is opened tto permit the uid in the loop to flow downwardly and drop below the level of the mold 10. A thy-pass valve 38 is opened so that pump 30 can keep running. During operation when the shell is Ibeing formed, the by-pa'ss valve 38 is of course closed, and a pressure control 45 may be used to maintain a uniform pressure of delivery of the stock to the mold 10 by the pump 30.

The discharge conduit 19 from the mold connects to the drop conduit 29 through a rotary connection 39 so that the conduit 19 can be swung upwardly away from the mold housing. The conduit 19, and the table surface 16 are provided with suitable annular seals so as to prevent leakage of tluid lat the connections to the housing.

Prior to swinging the conduit 19 upwardly, the agitator 27 is raised by operation of a fluid cylinder 40 with a piston 41 therein connected to a head 42. The head 42 raises the agitator 27 when fluid is admitted to the bottom of the cylinder 40, and the conduit 19 is then swung upwardly by a cylinder 44 having a piston therein connected to a rod 43 pivotally attached to the conduit 19.

FIGURE 2 shows a modified form of structure at the forming station with parts similar to FIGURE 1 being given similar numbers. Stock is supplied to the mold 1G by a stock supply line 46 connected to a stock pressure tank 47 having an air head -at the top and having a power driven agitator 48 therein. Air is supplied to the top of the tank at a predetermined constant temperature through a control valve 49, and a pressure release lbleed valve 50 is also connected to the tank top. By maintaining the air at a constant pressure, the stock S in the tank is supplied to the mold at a uniform pressure. This improves the deposition of fibers on the forming surface of the mold 10, and permits `accurate control of the thickness of the wall of the shell by timing the supply of stock to the mold 10.

Stock is supplied to the pressure tank 47 from a supply tank 51 having a rotating agitator 52 therein. A line 53 connects between the tanks 51 and 47, and a supply pump 54 pumps the stock S to the tank 47. A check valve 55 is located in the line 53.

An air dome 56 is positioned at the top of the housing 11. The air dome has a vent valve 57, and is supported on a pivotal arm 58 mounted on a bracket 59. A piston and cylinder 60 hold the air dome in place during forming of the shell, and raise the air dome out of the way when the shell and housing are moved to the succeeding station.

For forming the shell, a valve 61 is opened by a piston land cylinder 62 controlled by a sequence timer 63.

When the valve 61 is opened to permit the flow of stock up to the mold 10, the vent valve 57 is also opened sothat the stock can rise within the mold. The housing chamber 12 is pressurized to prevent depositing of fibers on the mold wall before the mold is completely filled with stock. When the mold is filled, the vent valve 57 is closed,4

and valve 22 is shifted to create a vacuum in the lhousing chamber 12 to cause the ow of liquid through the mold 10.

vFIGURE. 7 illustrates in schematic plan view the sequence of stations along the path, and shows dilerent process steps, as l-abeled, for three separate Iprocesses. The circled numbers below the steps of the process refer to the figures of the drawings land the structures thereof. For example, in each process, the forming `station has numbers 1 `and 2y indicated, which means that the structures of FIGURES 1 and 2 may be employed in that station. Similarly in the pressing station of ea-ch of the processes the numeral 3 -appears and this indicates that the structure of FIGURE 3 may be employed in this step, and similarly, the other steps indicate the structures which may =be employed.

Pressing stafion The structure of FIGURE 3 performs a pressing operation for flattening the fiber mat and squeezing moisture therefrom, applying a surface pressure to the inner exposed surface of the shell and pressing it outwardly against the smooth forming surface 2S of the mold 10. The mold housing 11 is carried along the stations of the machine by a traveling transfer -or carrier 64 arranged to slide on longitudinal rods or ways 65, and moves therealong by suitable power means, not shown. The housing is supported on the carrier 64 by Va head 66 which is arranged with a gripper or connecting means to grip the housing 11 securely, and release it at the end of the path to move back to the head of the machine for gripping another housing.

The head 66 is slidably mounted on a vertical guide rod 67 for vertical reciprocation to lift the housing olf the Surface 16 as it moves between stations, and to firmly lower the housing to the table surface 16 at the stations. A cylinder 68 is mounted on the carrier with a piston therein connected to a piston rod 69 connected to the head 66, and the cylinder is provided with suitable fluid connections for lifting the head. A control mechanism for timing the functions of this unit may take various forms which need not be shown in detail as will be appreciated by those skilled in the art. For example, a ca-m shaft rotated by timing motor and having a plurality of operating cams therealong may operate control switches for operating the various parts in their `appropriate sequence and for the proper times.

At the station of FIGURE 3, the agitator 27 and screen 26 have been removed from the mold 10, and an inflatable elongated ibladder 70 is inserted into the center lof the mold 10. The bladder is mounted on a vertical spindle 71 having .a lower portion 72 with air emission openings, which pressurize the interior of the bladder to force it outwardly against the inner surface of the shell. Air is directed to the interior of the bladder through `an air line 75 controlled by a valve 75a operated by a sequence timer 76.

The bladder is axially inserted into the open lower end of the mold for operation, and withdrawn therefrom in order to move the housing to the next station, by a piston rod 73 connected to a piston slidable within a cylinder 74 which has suitable connections and may be operated by a valve connected to the sequence timer 76.

Impregnation station In FIGURE 4 the shell supported within the mold 10 is impregnated with an impregnating or binding fluid. This fluid may be Ia solution of a compatible resinous impregnant and/ or binder, e.g. urea-formaldehyde or melamine-formaldehyde resins, cellulose esters and ethers, polyvinyl alcohols, etc. The resin may be in a 1% to 10% organic solvent solution or in aqueous emulsion.

The mold housing 11 is positioned in the impregnation station in alignment with an opening in the table 16 communicating with an impregnant supply line 77 controlled 6 by a Avalve 78. The line is connected to an impregnant tank 79 containing an impregnating liquid I. The tank is pressurized through an air line 80 leading to the upper end, and air pressure is controlled by a valve 81 operated by a sequence timer 82, which is also connected to the control valve'78.

Above the mold'housing 11 an air dome 83 is positioned having a vent control valve 84 connected thereto. The dome 83 is mounted on a pivotal valve 85 supported on a vbracket 87, and the dome is pivoted to the operative position shown, or pivoted out of the way of the housing, by a piston and cylinder 86, the cylinder being connected to suitable pressure operating lines.

The chamber 12 within the housing is rst pressurized through an air-vacuum line 88 and impregnant is admitted within the shell within the mold 10. The vent control valve 84 is opened so that Ithe impregnant can completely fill the inside of the shell, -and then closed. The chamber 12 is then subjected to a vacuum `through `line 88, and the impregnant penetrates the shell for a predetermined period of time. The impregnant is lthen drained out ofthe shell by relieving the pressure above the impregnant tank 79, and the housing v11 is moved onto to the next station. An overhead exhaust hood 89 carries away fumes from the impregnant.

Drying station In FIGURE 5 an elongated cylindrical perforate dryin g member 90 is axially inserted upwardly into the shell within the mold 10. The interior of the drying member 90 is connected to a Warm air line 91 having a valve 92 therein, controlled by the sequence timer 94. The sequence timer 94 is part of the same operating mechanism shown at 76 and 82 in FIGURES 3 and 4, and labeled sequence timer therein, but for convenience is provided with a separate number inasmuch as the unit will be operated through independent switches and operating mechanism although it may be operated in timed Yrelationship lto the other sequence timers.

Warm air is supplied to the line 91 from a warm air supply duct 93. The Warm air is directed outwardly through the perforations in the drying member 90 for a predetermined controlled length of time to evaporate moisture from the inner surface of the shell. The dryingis controlled and is terminated before the outer surface of the shell, which is in .contact with the inner forming surface 25, is completely dry. This facilitates separation of the shell from the forming surface. The pressure in the housing chamber 12 is reduced through the vacuum line 95.

The housing 11 is lifted vertically olf of the drying member 90 and then moved laterally to the vnext station.

Ejecton station yIn FIGURE 6 the housing is lowered to position the shell Within the mold 10 over a support mandrel 96. The mandrel has a perforated outer surface and a hollow interior to be connected to a suction line 98 controlled by a valve 99. The housing chamber 12 is pressurized through a release air line 97.

A feature of the process of transferring the shell from the mold l10 to the mandrel 96 resides in controlling the drying of the .shell so that the outer surface remains moist thereby vpermitting release of the outer surface of the shell from the finishing surface y25 of the mold.

When the shell is transferred to the mandrel 96, the housing and mold 10 are removed, and the shell is then carried to the oven, as shown in the processes of FIG- URE 7. Inasmuch as the mold 10 is slightly tapered, and the mandrel 96 fits snugly within the shell, and the inner surface of the shell has been dried and its dimensions iixed, the shell now has an accurate outer diameter and an accurate circular cross section. The size and shape will have been accurately and positively determined by the inner formingsurface 25 of lthe mold due 

1. IN A MECHANISM FOR FORMING A HOLLOW SHELL, THE COMBINATIN COMPRISING A POROUS SHAPED MOLD HAVING A FORMING SURFACE ON WHICH PARTICLES ARE DEPOSITED, SUPPLY MEANS FOR FORCING A FLUID STOCK HAVING PARTICLES IN SUSPENSION THROUGH THE MOLD TO DEPOSIT PARTICLES ON THE MOLD SURFACE, AND A SHAPED SCREEN CONFORMING TO THE SHAPE OF SAID FORMING SURFACE POSITONED IMMEDIATELY ADJACENT THE FORMING SURFACE SO THAT THE STOCK FLOWS THROUGH THE SCREEN IMMEDIATELY BEFORE REACHING THE FORMING SURFACE. 